BackgroundTo evaluate the potential of cerebrospinal fluid (CSF) levels of matrix metalloproteinases and tissue-type inhibitors (MMP; TIMP), and ratios of MMPs to TIMPs, to function as biomarkers... Show moreBackgroundTo evaluate the potential of cerebrospinal fluid (CSF) levels of matrix metalloproteinases and tissue-type inhibitors (MMP; TIMP), and ratios of MMPs to TIMPs, to function as biomarkers for sporadic or hereditary cerebral amyloid angiopathy (CAA).MethodsCSF concentrations of the matrix metalloproteinases MMP-2, MMP-9 and MMP-14, as well as the tissue inhibitors of metalloproteinases TIMP-1, TIMP-2 and TIMP-3, were determined using immunoassays. These assays were applied to two, independent study groups of sporadic CAA (sCAA) (n = 28/43) and control subjects (n = 40/40), as well as to groups of pre-symptomatic (n = 11) and symptomatic hereditary Dutch-CAA (D-CAA) patients (n = 12), and age-matched controls (n = 22/28, respectively).ResultsIn the sCAA/control cohorts, inconsistent differences were found for individual MMPs and TIMPs, but MMP-2/TIMP-2 (discovery/validation: p = 0.004; p = 0.02) and MMP-14/TIMP-2 ratios (discovery/validation: p < 0.001; p = 0.04) were consistently decreased in sCAA, compared to controls. Moreover, MMP-14 was decreased in symptomatic D-CAA (p = 0.03), compared to controls. The MMP-14/TIMP-1 (p = 0.03) and MMP-14/TIMP-2 (p = 0.04) ratios were decreased in symptomatic D-CAA compared to controls and also compared to pre-symptomatic D-CAA (p = 0.004; p = 0.005, respectively).ConclusionCSF MMP-2/TIMP-2 and MMP-14/TIMP-2 were consistently decreased in sCAA, compared to controls. Additionally, MMP-14/TIMP-2 levels were also decreased in symptomatic D-CAA, compared to both pre-symptomatic D-CAA and controls, and can therefore be considered a biomarker for sporadic and late-stage hereditary forms of CAA. Show less
Identification of translational and/or post-translational modifications of cardiac proteins after acute myocardial infarction (AMI) or during the progression to congestive heart failure (CHF) is... Show moreIdentification of translational and/or post-translational modifications of cardiac proteins after acute myocardial infarction (AMI) or during the progression to congestive heart failure (CHF) is relevant to gain insight into the pathological mechanisms. Characterization of the release kinetics of these cardiac proteins from the reversibly or irreversibly injured myocardium into the circulation may lead to new diagnostic biomarkers. Although cardiac Troponin I (cTnI) is a well-known biomarker of irreversible myocardial damage in acute myocardial infarction, we demonstrated that the release of cTnI also occurs from viable cardiomyocytes by a stretch-related mechanism, mediated by integrin stimulation. This finding may explain why in several pathological conditions, such as CHF, plasma cTnI levels are elevated in the absence of myocardial necrosis. In addition, we investigated the role of Tenascin-C re-expression during the development of heart failure and the relevance of TNC as a biomarker of ventricular remodeling. In animals with pressure-overload induced ventricle dilatation, TNC gene expression was upregulated, resulting in re-expression of myocardial TNC protein levels and elevated TNC plasma levels, correlating with cardiac function. Plasma TNC levels in patients with CHF declined during cardiac resynchronization therapy. This study indicates that serial plasma TNC levels can be used as a marker of adverse or reverse ventricular remodeling. Show less
